Variations in intraocular pressure during closed-system surgical procedures
L. C. Moorhead and C. D. Armeniades
True intraocular pressure (IOP) during closed-chamber anterior segment
surgery and vitrectomy was measured in rabbits by inserting a miniature
pressure sensor directly into the anterior chamber or into the vitreous.
Infusion fluid pressure was also measured simultaneously with a sensor in
the infusion line. Significant and rapid changes in IOP up to 110 mm Hg
were observed during routine anterior segment and vitreous procedures. None
of these IOP changes affected infusion line pressure, which was governed
solely by the infusion bottle height. Furthermore, raising the infusion
bottle produced minimal IOP elevation whenever fluid was flowing into and
out of the eye via a surgical instrument or a wound. These results show the
limitations of monitoring of infusion line pressure as a means for
assessing IOP and stress the need for IOP control during surgery.
